Polycarbonate resin composition and molded article thereof

ABSTRACT

The present invention relates to a polycarbonate resin composition, comprising: a polycarbonate resin containing a structural unit derived from a dihydroxy compound having a moiety represented by the following formula (1) [provided that a case where the moiety represented by formula (1) is a moiety constituting —CH 2 —O—H is excluded]; and an elastomer composed of a core●shell structure, wherein a core layer of the elastomer is composed of a butadiene-styrene copolymer, and a polycarbonate resin molded article obtained by molding the polycarbonate resin composition:
 
 CH 2 —O   (1).

TECHNICAL FIELD

The present invention relates to a polycarbonate resin compositionexcellent in the impact resistance, and a molded article thereof.

BACKGROUND ART

A polycarbonate is generally produced using a raw material derived frompetroleum resources. However, in recent years, depletion of petroleumresources is feared, and it is demanded to provide a polycarbonate usinga raw material obtained from biomass resources such as plant.

Also, because of a concern that global warming due to increase oraccumulation of carbon dioxide emissions may bring about climate changeor the like, it is demanded to develop a polycarbonate using aplant-derived monomer as a raw material and being carbon neutral evenwhen discarded after use.

A technique of obtaining a polycarbonate resin by using isosorbide as aplant-derived monomer and effecting transesterification with diphenylcarbonate has been recently proposed (see, for example, Patent Document1).

In the case of an aromatic polycarbonate resin that has been heretoforewidely used, the impact resistance of the resin itself is excellent, butwhen isosorbide is used, the impact resistance becomes poor as comparedwith the aromatic polycarbonate resin, and improvements are needed.

To solve this problem, a polycarbonate resin composition containing apolycarbonate resin having a high glass transition temperature and arubbery polymer has been proposed as a composition capable of enhancingthe impact resistance (see, for example, Patent Document 2).

BACKGROUND ART DOCUMENT Patent Document

Patent Document 1: British Patent 1,079,686

Patent Document 2: International Publication No. 08/146,719

SUMMARY OF INVENTION Problem that Invention is to Solve

However, even the polycarbonate resin composition described in PatentDocument 2 is not sufficient in its impact resistance, and moreimprovements are demanded.

Accordingly, an object of the present invention is to provide apolycarbonate resin composition excellent particularly in the impactresistance, and a molded article thereof.

Means for Solving Problem

As a result of a number of intensive studies to attain theabove-described object, the present inventors have found that apolycarbonate resin composition containing a polycarbonate resin with aspecific structure and an elastomer composed of a specific core●shellstructure is excellent in the impact resistance. The present inventionhas been accomplished based on this finding.

That is, the gist of the present invention resides in the following [1]to [12].

-   [1] A polycarbonate resin composition, comprising:

a polycarbonate resin containing a structural unit derived from adihydroxy compound having a moiety represented by the following formula(1); and

an elastomer composed of a core●shell structure,

wherein a core layer of the elastomer is composed of a butadiene-styrenecopolymer:[Chem. 1]

CH₂—O

  (1)[provided that a case where the moiety represented by formula (1) is amoiety constituting —CH₂—O—H is excluded].

-   [2] The polycarbonate resin composition as described in [1],

wherein when the polycarbonate resin composition is formed into a moldedbody of 3 mm in thickness, a total light transmittance is less than 60%.

-   [3] The polycarbonate resin composition as described in [1] or [2],    comprising the elastomer in an amount of 0.05 to 50 parts by weight    per 100 parts by weight of the polycarbonate resin.-   [4] The polycarbonate resin composition as described in any one of    [1] to [3],

wherein the polycarbonate resin contains a structural unit derived froma dihydroxy compound having a cyclic structure.

-   [5] The polycarbonate resin composition as described in [4],

wherein the polycarbonate resin contains a structural unit derived froma dihydroxy compound represented by the following formula (2):

-   [6] The polycarbonate resin composition as described in any one of    [1] to [5],

wherein a shell layer of the elastomer is composed of an alkyl(meth)acrylate.

-   [7] The polycarbonate resin composition as described in any one of    [1] to [6],

wherein the polycarbonate resin contains a structural unit derived froman aliphatic dihydroxy compound.

-   [8] The polycarbonate resin composition as described in [7],

wherein the polycarbonate resin contains the structural unit derivedfrom an aliphatic dihydroxy compound in an amount of 20 mol % or morebased on structural units derived from all dihydroxy compounds.

-   [9] The polycarbonate resin composition as described in any one of    [1] to [8],

wherein the polycarbonate resin contains a structural unit derived fromat least one dihydroxy compound selected from the group consisting of adihydroxy compound having a 5-membered ring structure and a dihydroxycompound having a 6-membered ring structure.

-   [10] The polycarbonate resin composition as described in any one of    [1] to [9],

wherein the polycarbonate resin contains a structural unit derived fromat least one dihydroxy compound selected from the group consisting ofcyclohexanedimethanols and tricyclodecanedimethanols.

-   [11] A polycarbonate resin molded article, which is obtained by    molding the polycarbonate resin composition as described in any one    of [1] to [10].-   [12] The polycarbonate resin molded article as described in [11],    which is obtained by injection-molding the polycarbonate resin    composition.

Effects of Invention

According to the present invention, a polycarbonate resin compositionexcellent particularly in the impact resistance, and a molded article ofthe polycarbonate resin composition can be provided. In a preferredembodiment, the polycarbonate resin composition of the present inventionis also excellent in various physical properties such as color hue, heatresistance and moldability.

MODE FOR CARRYING OUT INVENTION

The mode for carrying out the present invention is described in detailbelow, but the constituent requirements described below are mereexamples (representative examples) of the embodiment of the presentinvention, and the present invention is not limited to the followingcontents as long as its gist is observed. Incidentally, the expression“(numerical or physical value) to (numerical or physical value)” as usedin the description of the present invention is intended to include thenumerical or physical values before and after “to”. Also, in thedescription of the present invention, when a term “substituent” is used,unless otherwise indicated, the substituent is not limited in its kindand means a substituent having a molecular weight up to 200.

[Polycarbonate Resin Composition]

The polycarbonate resin composition of the present invention ischaracterized by comprising a polycarbonate resin containing astructural unit derived from a dihydroxy compound having a moietyrepresented by the following formula (1) [hereinafter, sometimesreferred to as “dihydroxy compound (1)”] and an elastomer composed of acore●shell structure with the core layer being composed of abutadiene-styrene copolymer:[Chem. 3]

CH₂—O

  (1)provided that a case where the moiety represented by formula (1) is amoiety constituting —CH₂—O—H is excluded.

The present invention is based on a finding that when a polycarbonateresin containing a structural unit derived from the dihydroxy compound(1) and an elastomer composed of a core●shell structure with the corelayer being composed of a butadiene-styrene copolymer are blended, animpact resistance improving effect unobtainable by the polycarbonateresin composition described in Patent Document 2 can be obtained.

In the polycarbonate resin composition of the present invention, whenthe polycarbonate resin composition is formed into a molded body of 3 mmin thickness, the total light transmittance is preferably less than 60%.Although this is described in detail later, a total light transmittanceof less than 60% is preferred particularly in using the composition, forexample, for application in a smoke film and the like, in a privacyglass for automobiles and the like, or in a glass-alternative buildingmaterial such as windowpane. In the applications above, the total lighttransmittance is preferably high to a certain extent for obtaininglighting and for this reason, the lower limit of the total lighttransmittance is preferably 20% or more.

The method for measuring the total light transmittance is described indetail later in Examples. The total light transmittance can becontrolled, for example, by increasing the blending amount of theelastomer in the polycarbonate resin composition or blending variouspigments or dyes or by a combination thereof.

[Polycarbonate Resin]

The polycarbonate resin for use in the polycarbonate resin compositionof the present invention (hereinafter, sometimes referred to as “thepolycarbonate resin of the present invention”) contains a structuralunit derived from a dihydroxy compound having a moiety represented bythe following formula (1) [dihydroxy compound (1)]:[Chem. 4]

CH₂—O

  (1)provided that a case where the moiety represented by formula (1) is amoiety constituting —CH₂—O—H is excluded.

The polycarbonate resin for use in the present invention can be obtainedby using a dihydroxy compound (1) and a carbonic acid diester as rawmaterials and polycondensing these material through atransesterification reaction therebetween.

<Raw Material>

(Dihydroxy Compound)

The polycarbonate resin of the present invention preferably contains astructural unit derived from a dihydroxy compound (1). The dihydroxycompound (1) is not particularly limited as log as it is a compoundhaving a moiety represented by formula (1) in a part of the structure.

Specific examples thereof include oxyalkylene glycols such as diethyleneglycol, triethylene glycol and tetraethylene glycol, a compound havingan aromatic group in the side chain and having, in the main chain, anether group bonded to an aromatic group, such as9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3 sobutylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-tert-butylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-cyclohexylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene,9,9-bis[4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl]fluorene and9,9-bis[4-(3-hydroxy-2,2-dimethylpropoxy)phenyl]fluorene, an anhydroussugar alcohol typified by a dihydroxy compound represented by thefollowing general formula (2), and a compound having a cyclic etherstructure, such as spiro glycol represented by the following formula (3)and dihydroxy compound represented by the following formula (4).

Among these dihydroxy compounds (1), in view of availability, handling,reactivity during polymerization, and color hue of the polycarbonateresin obtained, diethylene glycol and triethylene glycol are preferred.In view of heat resistance or light resistance, a sugar alcoholrepresented by the following formula (2) and a dihydroxy compound havinga cyclic ether structure, such as spiro glycol represented by thefollowing formula (3) and dihydroxy compound represented by thefollowing formula (4), are preferred, a sugar alcohol typified by adihydroxy compound represented by the following formula (2) and adihydroxy compound having a cyclic ether structure composed of aplurality of rings, such as spiro glycol represented by the followingformula (3), preferably having a cyclic ether structure composed of tworings, are more preferred, and an anhydrous sugar alcohol typified by adihydroxy compound represented by the following formula (2) is stillmore preferred. One of these compounds may be used alone, or two or morethereof may be used in combination, according to the performancerequired of the polycarbonate resin obtained.

The dihydroxy compound represented by formula (2) includes, for example,isosorbide, isomannide, and isoidide, which are stereoisomers. One ofthese compounds may be used alone, or two or more thereof may be used incombination.

Among these dihydroxy compounds (1), use of a dihydroxy compound havingno aromatic ring structure is preferred in view of light resistance ofthe polycarbonate resin obtained, and among others, an isosorbide thatis obtained by dehydration condensation of sorbitol produced fromvarious starches existing abundantly as a plant-derived resource andbeing easily available, is most preferred from the aspect ofavailability, ease of production, light resistance, opticalcharacteristics, moldability, heat resistance and carbon neutral.

The ratio of the structural unit derived from the dihydroxy compound (1)to structural units derived from all dihydroxy compounds in thepolycarbonate resin is preferably 10 mol % or more, more preferably 20mol % or more, still more preferably 30 mol % or more. On the otherhand, the ratio of the structural unit derived from the dihydroxycompound (1) to structural units derived from all dihydroxy compounds inthe polycarbonate resin is preferably 60 mol % or less, more preferably55 mol % or less. By containing the structural unit derived from thedihydroxy compound (1) in the above-described predetermined amount, thepolycarbonate resin can excel in the color tone, light resistance andthe like.

Also, in order to impart flexibility or ductility, the polycarbonateresin of the present invention preferably contains a structural unitderived from an aliphatic dihydroxy compound (a dihydroxy compound wherethose except for two hydroxy groups are composed of an aliphatichydrocarbon), in addition to a structural unit derived from thedihydroxy compound (1). Introducing a structural unit derived from analiphatic dihydroxy compound into the polycarbonate resin may beattained by using an aliphatic dihydroxy compound as a raw material ofthe polycarbonate resin and copolymerizing it, similarly to thedihydroxy compound (1).

The aliphatic dihydroxy compound includes, for example, a straight-chainaliphatic dihydroxy compound, a branched-chain aliphatic dihydroxycompound, and an alicyclic dihydroxy compound. Among these, an alicyclicdihydroxy compound is preferred.

Specific examples of the aliphatic dihydroxy compound which can be usedin the present invention are recited below, and only one of thesealiphatic dihydroxy compounds may be used, or two or more thereof may beused in combination.

Examples of the straight-chain aliphatic dihydroxy compound includeethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol,1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol,1,10-decanediol, and 1,12-dodecanediol. Examples of the branched-chainaliphatic dihydroxy compound include neopentyl glycol and hexyleneglycol.

The alicyclic dihydroxy compound is a compound having a hydrocarbonframework of a cyclic structure and two hydroxy groups, and the hydroxygroup may be bonded directly to the cyclic structure or may be bonded tothe cyclic structure through a substituent such as alkylene group. Thecyclic structure may be monocyclic or polycyclic.

The alicyclic dihydroxy compound is, for example, an alicyclic dihydroxycompound having a 5-membered ring structure or an alicyclic dihydroxycompound having a 6-membered ring structure, which are described below.An alicyclic dihydroxy compound having a 5-membered ring structure or analicyclic dihydroxy compound having a 6-membered ring structure is usedas the alicyclic dihydroxy compound, and a structural unit derived fromthe compound is introduced into the polycarbonate resin, whereby heatresistance of the polycarbonate resin can be enhanced.

The carbon number of the alicyclic dihydroxy compound is usuallypreferably 70 or less, more preferably 50 or less, still more preferably30 or less. As the carbon number is larger, the heat resistance of thepolycarbonate resin obtained tends to be higher, but the synthesis orpurification of the polycarbonate resin may become difficult or the costmay rise, whereas as the carbon number of the alicyclic dihydroxycompound is smaller, the purification is easier and the raw materialprocurement is facilitated.

Examples of the alicyclic dihydroxy compound having a 5-membered ringstructure include tricyclodecanediols; pentacyclopentadecanediols;decalindiols such as 2,6-decalindiol, 1,5-decalindiol and2,3-decalindiol; tricyclotetradecanediols; tricyclodecanedimethanols;and pentacyclopentadecanedimethanols.

Examples of the alicyclic dihydroxy compound having a 6-membered ringstructure include cyclohexanediols such as 1,2-cyclohexanediol,1,3-cyclohexanediol, 1,4-cyclohexanediol, and2-methyl-1,4-cyclohexanediol; cyclohexenediols such as4-cyclohexene-1,2-diol; norbornanediols such as 2,3-norbornanediol and2,5-norbornanediol; adamantanediols such as 1,3-adamantanediol and2,2-adamantanediol; cyclohexanedimethanols such as1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and1,4-cyclohexanedimethanol; cyclohexenedimethanols such as4-cyclohexene-1,2-dimethanol; norbornanedimethanols such as2,3-norbornanedimethanol and 2,5-norbornanedimethanol; andadamantanedimethanols such as 1,3-adamantanedimethanol and2,2-adamantanedimethanol.

Among these alicyclic dihydroxy compounds, cyclohexanedimethanols,tricyclodecanedimethanols, adamantanediols andpentacyclopentadecanedimethanols are preferred, andcyclohexanedimethanols and tricyclodecanedimethanol are more preferred.

When cyclohexanedimethanols are used, the obtained polycarbonate resintends to be increased particularly in the flexibility or ductility, andthanks to use together with the later-described elastomer having a corelayer composed of a butadiene-styrene copolymer, the impact resistancein particular becomes excellent. Also, when tricyclodecanedimethanolsare used, the polycarbonate resin obtained tends to have an excellentbalance between surface hardness and ductility. Amongcyclohexanedimethanols, 1,4-cyclohexanedimethanol is preferred.

Thanks to a configuration where the polycarbonate resin contains both astructural unit derived from the dihydroxy compound (1) and a structuralunit derived from an aliphatic dihydroxy compound such as alicyclicdihydroxy compound, an effect of not only improving the transparency orimpact resistance of the polycarbonate resin but also improving variousphysical properties such as flexibility, heat resistance and moldabilitycan be obtained.

If the proportion of the structural unit derived from an aliphaticdihydroxy compound such as alicyclic dihydroxy compound in thepolycarbonate resin of the present invention is too small, thepolycarbonate resin composition formed tends to suffer from baddispersion of the elastomer in the polycarbonate resin and be reduced inthe effect of improving the surface impact resistance.

If the proportion of the structural unit derived from an aliphaticdihydroxy compound such as alicyclic dihydroxy compound in thepolycarbonate resin of the present invention is too large, the reducedviscosity of the polycarbonate resin may become high to cause reductionin the flowability during molding and worsen the productivity ormoldability.

In particular, when the ratio of the structural unit derived from thealiphatic dihydroxy compound to structural units derived from alldihydroxy compounds in the polycarbonate resin is 20 mol % or more, thepolycarbonate resin composition formed can excel in the lightreflectance or impact resistance.

The ratio of the structural unit derived from an aliphatic dihydroxycompound such as alicyclic dihydroxy compound to structural unitsderived from all dihydroxy compounds in the polycarbonate resin ispreferably 20 mol % or more, more preferably 40 mol % or more, stillmore preferably 45 mol % or more.

On the other hand, the ratio of the structural unit derived from analiphatic dihydroxy compound such as alicyclic dihydroxy compound tostructural units derived from all dihydroxy compounds in thepolycarbonate resin is preferably 90 mol % or less, more preferably 80mol % or less, still more preferably 70 mol % or less. As the ratio ofthe structural unit derived from an aliphatic dihydroxy compound ishigher in the range above, the impact resistance tends to be moreexcellent.

Incidentally, in the polycarbonate resin of the present invention, astructural unit deemed to come under both a structural unit derived fromthe dihydroxy compound (1) and a structural unit derived from analiphatic dihydroxy compound may be contained. In the case of containingsuch a structural unit, after satisfying the requirement of containingat least a structural unit derived from the dihydroxy compound (1), thestructural unit deemed to come under both a structural unit derived fromthe dihydroxy compound (1) and a structural unit derived from analiphatic dihydroxy compound may be arbitrarily classed.

The polycarbonate resin of the present invention may contain astructural unit derived from a dihydroxy compound other than thedihydroxy compound (1) and the aliphatic dihydroxy compound(hereinafter, sometimes referred to as “other dihydroxy compounds”).

More specifically, the other dihydroxy compounds include, for example,aromatic bisphenols such as 2,2-bis(4-hydroxyphenyl)propane [=bisphenolA], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,2,2-bis(4-hydroxy-3,5-diethylphenyl)propane,2,2-bis[4-hydroxy-(3,5-diphenyl)phenyl]propane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,2,2-bis(4-hydroxyphenyl)pentane, 2,4′-dihydroxy-diphenylmethane,bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane,1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone,2,4′-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl)sulfide,4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenylether, 9,9-bis(4-hydroxyphenyl)fluorene, and9,9-bis(4-hydroxy-2-methylphenyl)fluorene.

In view of light resistance of the polycarbonate resin, the otherdihydroxy compound is preferably a compound having no aromatic ringstructure in the molecular structure. One of these other dihydroxycompounds may be used alone, or two or more thereof may be used incombination, according to the performance required of the polycarbonateresin obtained.

In the case where the polycarbonate resin of the present inventioncontains a structural unit derived from other dihydroxy compounds, theratio of the structural unit derived from the other dihydroxy compoundto structural units derived from all dihydroxy compounds in thepolycarbonate resin is preferably 40 mol % or less, more preferably 30mol % or less, still more preferably 20 mol % or less, yet still morepreferably 10 mol % or less.

The dihydroxy compound for use in the production of the polycarbonateresin of the present invention may contain a stabilizer such as reducingagent, antioxidant, oxygen scavenger, light stabilizer, antacid, pHstabilizer and heat stabilizer. Particularly, under acidic conditions,the dihydroxy compound is susceptible to property change and therefore,preferably contains a basic stabilizer.

Examples of the basic stabilizer include a hydroxide, a carbonate, aphosphate, a phosphite, a hypophosphite, a borate and a fatty acid salt,of a metal belonging to Group 1 or 2 of the long-form periodic table(Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005); abasic ammonium compound such as tetramethylammonium hydroxide,tetraethyl ammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, trimethylethylammonium hydroxide,trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide,triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide,triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide,tributylphenylammonium hydroxide, tetraphenylammonium hydroxide,benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide andbutyltriphenylammonium hydroxide; and an amine-based compound such as4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine,4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine,4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole,imidazole, 2-mercaptoimidazole, 2-methylimidazole and aminoquinoline.Among others, a phosphate and a phosphite of sodium or potassium arepreferred in view of the effect and the later-described easy removal bydistillation, and disodium hydrogen phosphate and disodium hydrogenphosphite are more preferred.

The content of the basic stabilizer in the dihydroxy compound is notparticularly limited, but if the content is too small, the effect ofpreventing property change of the dihydroxy compound may not beobtained, whereas if the content is too large, this may cause propertymodification of the dihydroxy compound. Therefore, usually, the contentis preferably from 0.0001 to 1 wt %, more preferably from 0.001 to 0.1wt %, based on the dihydroxy compound.

Also, when the dihydroxy compound containing such a basic stabilizer isused as a raw material for the production of the polycarbonate resin,the basic stabilizer not only serves itself as a polymerizationcatalyst, making it difficult to control the polymerization rate andquality, but also involves worsening of the initial color to impair thelight resistance of the polycarbonate resin molded article obtained.Therefore, before using the dihydroxy compound as a raw material for theproduction of the polycarbonate resin, the basic stabilizer ispreferably removed by using an ion-exchange resin, distillation or thelike.

In the case of a dihydroxy compound containing a cyclic ether structure,such as isosorbide, the dihydroxy compound is likely to be graduallyoxidized by oxygen and therefore, it is preferred to inhibit waterinclusion during storage or production for preventing decomposition byoxygen and use an oxygen scavenger or the like or treat the dihydroxycompound in a nitrogen atmosphere. When isosorbide is oxidized, adecomposition product such as formic acid may be generated. For example,when isosorbide containing such a decomposition product is used as a rawmaterial for the production of the polycarbonate resin, this may lead tocoloring of the polycarbonate resin obtained or may not only be involvedin significant deterioration of the physical properties but also affectthe polymerization reaction, failing in obtaining a polymer having ahigh molecular weight.

In order to obtain a dihydroxy compound free from the above-describedoxidation decomposition product or remove the basic stabilizer, it ispreferred to perform distillation/purification of the dihydroxycompound. The distillation in this case may be simple distillation orcontinuous distillation and is not particularly limited. As for thedistillation conditions, distillation is preferably performed underreduced pressure in an inert gas atmosphere such as argon or nitrogen,and from the standpoint of preventing property modification due to heat,distillation is preferably performed under the condition of preferably250° C. or less, more preferably 200° C. or less, still more preferably180° C. or less.

Through such distillation/purification, the content of formic acid inthe dihydroxy compound for use in the present invention is reduced to 20ppm by weight or less, preferably 10 ppm by weight or less, morepreferably 5 ppm by weight or less, whereby a polycarbonate resinexcellent in the color hue and thermal stability can be produced withoutimpairing the polymerization reactivity during production of thepolycarbonate resin. Measurement of the formic acid content is performedby ion chromatography.

(Carbonic Acid Diester)

The polycarbonate resin of the present invention can be obtained byusing a dihydroxy compound containing the above-described dihydroxycompound (1) and a carbonic acid diester as raw materials andpolycondensing these materials through a transesterification reactiontherebetween.

The carbonic acid diester used includes usually a compound representedby the following formula (5). One of these carbonic acid diesters may beused alone, or two or more thereof may be mixed and used.

In formula (5), each of A¹ and A² is independently a substituted orunsubstituted aliphatic hydrocarbon group having a carbon number of 1 to18 or a substituted or unsubstituted aromatic hydrocarbon group. Each ofA¹ and A² is preferably a substituted or unsubstituted aromatichydrocarbon group, more preferably an unsubstituted aromatic hydrocarbongroup.

Examples of the carbonic aid diester represented by formula (5) includediphenyl carbonate, a substituted diphenyl carbonate such as ditolylcarbonate, dimethyl carbonate, diethyl carbonate, and di-tert-butylcarbonate. Among these, diphenyl carbonate and a substituted diphenylcarbonate are preferred, and diphenyl carbonate is more preferred.

Incidentally, the carbonic acid diester sometimes contains an impuritysuch as chloride ion, and the impurity may inhibit the polymerizationreaction or worsen the color hue of the polycarbonate resin obtained.Therefore, it is preferred to use a carbonic acid diester that has beenpurified by distillation or the like as needed.

<Transesterification Reaction Catalyst>

The polycarbonate resin of the present invention is produced usually bya transesterification reaction between a dihydroxy compound containingthe dihydroxy compound (1) and a carbonic acid diester represented byformula (5). More specifically, a dihydroxy compound containing thedihydroxy compound (1) and a carbonic acid diester represented byformula (5) are polycondensed by a transesterification reaction, and amonohydroxy compound or the like produced as a by-product is removed outof the system, whereby the polycarbonate resin is obtained. In thiscase, the polycondensation is usually performed by a transesterificationreaction in the presence of a transesterification reaction catalyst.

The transesterification reaction catalyst (hereinafter, sometimes simplyreferred to as “catalyst” or “polymerization catalyst”) which can beused in the production of the polycarbonate resin of the presentinvention may affect the transparency or color hue in particular.

The catalyst used is not limited as long as it can satisfy the lightresistance, transparency, color hue, heat resistance, thermal stabilityand mechanical strength, among others, the light resistance, of theproduced polycarbonate resin, but the catalyst includes, for example, acompound of a metal belonging to Group 1 or 2 of the long-form periodictable (hereinafter, simply referred to as “Group 1” or “Group 2”), and abasic compound such as basic boron compound, basic phosphorus compound,basic ammonium compound and amine-based compound. Preferably, a Group 1metal compound and/or a Group 2 metal compound are used.

Together with a Group 1 metal compound and/or a Group 2 metal compound,a basic compound such as basic boron compound, basic phosphoruscompound, basic ammonium compound and amine-based compound may besecondarily used in combination, but it is particularly preferred to useonly a Group 1 metal compound and/or a Group 2 metal compound.

As for the form of the Group 1 metal compound and/or Group 2 metalcompound, the compound is usually used in the form of a hydroxide or asalt such as carbonate, carboxylate and phenoxide, but a hydroxide, acarbonate and an acetate are preferred in view of availability andhandleability, and an acetate is preferred in view of color hue andpolymerization activity.

The Group 1 metal compound includes, for example, sodium hydroxide,potassium hydroxide, lithium hydroxide, cesium hydroxide, sodiumhydrogencarbonate, potassium hydrogencarbonate, lithiumhydrogencarbonate, cesium hydrogencarbonate, sodium carbonate, potassiumcarbonate, lithium carbonate, cesium carbonate, sodium acetate,potassium acetate, lithium acetate, cesium acetate, sodium stearate,potassium stearate, lithium stearate, cesium stearate, sodium boronhydride, potassium boron hydride, lithium boron hydride, cesium boronhydride, sodium boron phenylate, potassium boron phenylate, lithiumboron phenylate, cesium boron phenylate, sodium benzoate, potassiumbenzoate, lithium benzoate, cesium benzoate, disodium hydrogenphosphate,dipotassium hydrogenphosphate, dilithium hydrogenphosphate, dicesiumhydrogenphosphate, disodium phenylphosphate, dipotassiumphenylphosphate, dilithium phenylphosphate, dicesium phenylphosphate,alcoholates and phenolates of sodium, potassium, lithium and cesium, anddisodium, dipotassium, dilithium and dicesium salts of bisphenol A.Among these, a lithium compound is preferred.

The Group 2 metal compound includes, for example, calcium hydroxide,barium hydroxide, magnesium hydroxide, strontium hydroxide, calciumhydrogencarbonate, barium hydrogencarbonate, magnesiumhydrogencarbonate, strontium hydrogencarbonate, calcium carbonate,barium carbonate, magnesium carbonate, strontium carbonate, calciumacetate, barium acetate, magnesium acetate, strontium acetate, calciumstearate, barium stearate, magnesium stearate, and strontium stearate.Among these, a magnesium compound, a calcium compound and a bariumcompounds are preferred, a magnesium compound and/or a calcium compoundare more preferred in view of the polymerization activity and color hueof the obtained polycarbonate resin, and a calcium compound is mostpreferred.

The basic boron compound includes, for example, sodium, potassium,lithium, calcium, barium, magnesium and strontium salts oftetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron,trimethylethylboron, trimethylbenzylboron, trimethylphenylboron,triethylmethylboron, triethylbenzylboron, triethylphenylboron,tributylbenzylboron, tributylphenylboron, tetraphenylboron,benzyltriphenylboron, methyltriphenylboron and butyltriphenylboron.

The basic phosphorus compound includes, for example, triethylphosphine,tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine,triphenylphosphine, tributylphosphine, and a quaternary phosphoniumsalt.

The basic ammonium compound includes, for example, tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, trimethylethylammonium hydroxide,trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide,triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide,triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide,tributylphenylammonium hydroxide, tetraphenylammonium hydroxide,benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide,and butyltriphenylammonium hydroxide.

The amine-based compound includes, for example, 4-aminopyridine,2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine,2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine,2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole,2-mercaptoimidazole, 2-methylimidazole, and aminoquinoline.

Of these compounds, a least one metal compound selected from the groupconsisting of a lithium compound and a compound of a metal belonging toGroup 2 of the long-form periodic table is preferably used as thecatalyst so as to obtain a polycarbonate resin excellent in variousphysical properties such as transparency, color hue and lightresistance.

Also, in order to make the polycarbonate resin of the present inventionexcel particularly in the transparency, color hue and light resistance,the catalyst is preferably at least one metal compound selected from thegroup consisting of a magnesium compound and a calcium compound.

The amount of the polymerization catalyst used is preferably from 0.1 to300 μmol, more preferably from 0.5 to 100 μmol, per mol of all dihydroxycompounds used for the polymerization. Among other, in the case of usinga compound containing at least one metal selected from the groupconsisting of lithium and Group 2 of the long-form periodic table,particularly, in the case of using a magnesium compound and/or a calciumcompound, the amount of the catalyst is, in terms of metal amount,preferably 0.1 μmol or more, more preferably 0.5 μmol or more, stillmore preferably 0.7 μmol or more, per mol of all dihydroxy compounds.The upper limit is preferably 20 μmol, more preferably 10 μmol, stillmore preferably 3 μmol, and most preferably 2.0 μmol.

If the amount of the catalyst used is too small, the polymerization ratedecreases, as a result, the polymerization temperature must be raised soas to obtain a polycarbonate resin having a desired molecular weight,leading to worsening of the color hue or light resistance of theobtained polycarbonate resin, or an unreacted raw material mayvolatilize during polymerization to disrupt the mol ratio between adihydroxy compound containing the dihydroxy compound (1) and thecarbonic acid diester represented by formula (5), failing in reachingthe desired molecular weight. On the other hand, if the amount of thepolymerization catalyst used is too large, this may cause worsening ofthe color hue of the obtained polycarbonate resin and in turn, the lightresistance of the polycarbonate resin may be impaired.

<Production Process of Polycarbonate Resin>

The polycarbonate resin of the present invention is obtained bypolycondensing a dihydroxy compound containing the dihydroxy compound(1) and a carbonic acid diester of formula (5) through atransesterification reaction therebetween, and the dihydroxy compoundand the carbonic acid diester as raw materials are preferably mixeduniformly before the transesterification reaction.

The mixing temperature above is usually preferably 80° C. or more, morepreferably 90° C. or more, and the upper limit thereof is usuallypreferably 250° C. or less, more preferably 200° C. or less, still morepreferably 150° C. or less. Above all, the mixing temperature ispreferably form 95 to 120° C. If the mixing temperature is too low, aslow dissolution rate or insufficient solubility may result and atrouble such as solidification is often caused, whereas if the mixingtemperature is too high, this may invite thermal deterioration of thedihydroxy compound, as a result, the color hue of the obtainedpolycarbonate resin may be worsened to adversely affect the lightresistance.

Also, from the standpoint of preventing worsening of the color hue ofthe obtained polycarbonate resin, the operation of mixing a dihydroxycompound containing the dihydroxy compound (1) and a carbonic aciddiester represented by formula (5) is preferably performed in anatmosphere having an oxygen concentration of preferably 10 vol % orless, more preferably from 0.0001 to 10 vol %, still more preferablyfrom 0.0001 to 5 vol %, yet still more preferably from 0.0001 to 1 vol%.

The carbonic acid diester represented by formula (5) is preferably usedin a mol ratio of 0.90 to 1.20, more preferably from 0.95 to 1.10, basedon the dihydroxy compound containing the dihydroxy compound (1).

If this mol ratio is too small, the content of the terminal hydroxylgroup of the polycarbonate resin produced may be increased, giving riseto worsening of the thermal stability of the polycarbonate resin,occurrence of coloring during molding, reduction in thetransesterification reaction rate, or failure in obtaining a desiredhigh-molecular polymer.

Also, if the mol ratio is too large, this may cause reduction in thetransesterification reaction rate or make it difficult to produce apolycarbonate resin having a desired molecular weight. The reduction inthe transesterification reaction rate leads to an increase in the heathistory during polymerization reaction and in turn, worsening of thecolor hue or light resistance of the polycarbonate resin obtained.

Furthermore, if the mol ratio of the carbonic acid diester representedby formula (5) to the dihydroxy compound containing the dihydroxycompound (1) is increased, there is a tendency that the amount of thecarbonic acid diester remaining in the obtained polycarbonate resinincreases and such a residual carbonic acid diester absorbs anultraviolet ray to worsen the light resistance of the polycarbonateresin.

The concentration of the carbonic acid diester remaining in thepolycarbonate resin of the present invention is preferably 200 ppm byweight or less, more preferably 100 ppm by weight or less, still morepreferably 60 ppm by weight or less, yet still more preferably 30 ppm byweight or less. The polycarbonate resin composition actually sometimescontains an unreacted carbonic acid diester, and the lower limit of theconcentration of the unreacted carbonic acid diester in thepolycarbonate resin is usually 1 ppm by weight.

In the present invention, the method for causing polycondensation of thedihydroxy compound and the carbonic acid diester is performed in thepresence of the above-described catalyst usually in multiple stages byusing a plurality of reaction vessels. The mode of reaction operationmay be any of a batch system, a continuous system, and a combination ofa batch system and a continuous system.

As for the polymerization conditions, the polymerization is preferablyperformed at a relatively low temperature under relatively low vacuum inits initial stage to obtain a prepolymer and performed at a relativelyhigh temperature under relatively high vacuum in the later stage ofpolymerization to increase the molecular weight to a predeterminedvalue, but in view of color hue and light resistance of the obtainedpolycarbonate resin, it is important to appropriately select the jackettemperature, the internal temperature and the pressure inside thereaction system for each molecular weight stage. For example, if eitherone of the temperature and the pressure is changed too early before thepolymerization reaction reaches a predetermined value, an unreactedmonomer may be distilled off to disrupt the mol ratio between thedihydroxy compound and the carbonic acid diester, leading to a drop ofthe polymerization rate.

Furthermore, for reducing the amount of a monomer distilled off, it iseffective to use a reflux condenser in the polymerization reactionvessel, and the effect thereof is great particularly in the reactionvessel at the initial polymerization stage involving generation of manyunreacted monomers. The temperature of the cooling medium introducedinto the reflux condenser may be appropriately selected according to themonomers used, but the temperature of the cooling medium introduced intothe reflux condenser is, at the inlet of the reflux condenser, usuallypreferably from 45 to 180° C., more preferably from 80 to 150° C., stillmore preferably from 100 to 130° C. If the temperature of the coolingmedium introduced into the reflux condenser is too high, the refluxamount decreases to reduce the effect, whereas if the temperature is toolow, the distillation efficiency for the monohydroxy compound thatshould be originally removed by distillation tends to decrease. Thecooling medium includes, for example, warm water, steam, and heatingmedium oil, and steam or a heating medium oil is preferred.

In order not to impair the color hue, thermal stability, lightresistance and the like of the finally obtained polycarbonate resinwhile appropriately maintaining the polymerization rate and suppressingdistillation off of monomers, selection of the kind and amount of thecatalyst described above is important.

The polycarbonate resin of the present invention is preferably producedby using a catalyst and performing the polymerization in multiple stageswith use of a plurality of reaction vessels, and the reason why thepolymerization is performed using a plurality of reaction vessels isthat: in the initial stage of polymerization reaction, the content ofmonomers in the reaction solution is large and therefore, it isimportant to suppress volatilization of monomers while maintaining anecessary polymerization rate; and in the later stage of polymerizationreaction, it is important to sufficiently distill off the by-productmonohydroxy compound so as to shift the equilibrium to thepolymerization side. For setting different polymerization reactionconditions in this way, a plurality of polymerization reaction vesselsarranged in series are preferably used in view of production efficiency.

The number of reaction vessels used in the production of thepolycarbonate resin of the present invention is, as described above,preferably at least 2 or more, and in view of production efficiency andthe like, more preferably 3 or more, still more preferably from 3 to 5,yet still more preferably 4. In the present invention, when two or morereaction vessels are used, the reaction vessels may be designed to, forexample, further have a plurality of reaction stages differing in theconditions or be continuously changed in the temperature●pressure.

In the present invention, the polymerization catalyst may be added to araw material preparation tank or a raw material storage tank or may beadded directly to a polymerization tank, but in view of feed stabilityand polymerization control, the catalyst is preferably fed in the formof an aqueous solution by disposing a catalyst feed line in the middleof a raw material line before feeding to a polymerization tank.

If the polymerization reaction temperature is too low, this may lead toa decrease in productivity or an increase in heat history of theproduct, whereas if the temperature is too high, not only volatilizationof monomers is caused but also decomposition or coloring of the obtainedpolycarbonate resin may be promoted.

The polymerization reaction is specifically performed, for example, byallowing the reaction in the first stage to proceed at a temperature of,in terms of maximum internal temperature of the polymerization reactionvessel, preferably from 140 to 270° C., more preferably from 180 to 240°C., still more preferably from 200 to 230° C., under a pressure of, interms of absolute pressure, preferably from 110 to 10 kPa, morepreferably from 70 to 5 kPa, still more preferably from 30 to 1 kPa, fora reaction time of preferably from 0.1 to 10 hours, more preferably from0.5 to 3 hours, while removing the generated monohydroxy compound bydistillation out of the reaction system.

In the second and subsequent stages, the pressure (absolute pressure) ofthe reaction system is caused to finally reach preferably 200 Pa or lessby gradually lowering the pressure of the reaction system from thepressure in the first stage, and the reaction is performed at a maximuminternal temperature of the polymerization reaction vessel of preferablyfrom 210 to 270° C., more preferably from 220 to 250° C., usually forpreferably from 0.1 to 10 hours, more preferably from 1 to 6 hours,still more preferably from 0.5 to 3 hours, while removing thecontinuously generated monohydroxy compound out of the reaction system.

Above all, in order to obtain a polycarbonate resin excellent in thecolor hue and light resistance by preventing coloring or thermaldeterioration of the obtained polycarbonate resin, the maximum internaltemperature in all reaction stages is preferably less than 250° C.,particularly preferably from 225 to 245° C. Also, for inhibiting a dropof the polymerization rate in the latter half of the polymerizationreaction and minimizing deterioration due to heat history, a horizontalreaction vessel excellent in the plug-flow properties and interfacerenewal properties is preferably used in the final stage ofpolymerization.

If a high polymerization temperature and a too long polymerization timeare employed so as to increase the molecular weight of the obtainedpolycarbonate resin, the transparency or color hue tends to be worsened.

In view of effective utilization of resources, the by-productmonohydroxy compound is preferably purified, if desired, and then reusedas a raw material of diphenyl carbonate, bisphenol A or the like.

Here, in the case of producing the polycarbonate resin by using, as thecarbonic acid diester represented by formula (5), diphenyl carbonate ora substituted diphenyl carbonate such as ditolyl carbonate, phenol or asubstituted phenol is unavoidably produced as a by-product and remainsin the polycarbonate resin, and both phenol and a substituted phenolhave an aromatic ring and not only may absorb an ultraviolet ray,leading to worsening of the light resistance, but also may give rise toan odor during molding.

The polycarbonate resin after a normal batch reaction contains 1,000 ppmby weight or more of an aromatic monohydroxy compound having an aromaticring, such as by-product phenol, and in view of light resistance orreduction in the odor, the content of the aromatic monohydroxy compoundin the polycarbonate resin is preferably reduced to 700 ppm by weight orless, more preferably 500 ppm by weight or less, still more preferably300 ppm by weight or less, by using a horizontal reaction vesselexcellent in the devolatilizing performance or using an extruder with avacuum vent.

However, it is industrially difficult to completely remove the aromaticmonohydroxy compound, and the lower limit of the content of the aromaticmonohydroxy compound in the polycarbonate resin is usually 1 ppm byweight. Incidentally, such an aromatic monohydroxy compound may ofcourse have a substituent depending on the raw materials used and mayhave, for example, an alkyl group having a carbon number of 5 or less.

Also, a Group 1 metal, among others, lithium, sodium, potassium andcesium, particularly, sodium, potassium and cesium, may migrate not onlyfrom the catalyst used but also from the raw material or reactionapparatus, and such a metal, when contained in a large amount in thepolycarbonate resin, may adversely affect the color hue. Therefore, thetotal amount of these compounds in the polycarbonate resin of thepresent invention is preferably smaller and is usually, in terms ofmetal amount, preferably 1 ppm by weight or less, more preferably 0.8ppm by weight or less, still more preferably 0.7 ppm by weight or less.

The metal amount in the polycarbonate resin can be measured by variousconventionally known methods. For example, the method that the metal inthe polycarbonate resin composition is recovered by a wet ashing methodor the like, and thereafter, the metal amount is measured by atomicemission, atomic absorption, Inductively Coupled Plasma (ICP) or othermethods can be exemplified.

The polycarbonate resin of the present invention is usuallycooled/solidified after polycondensation as described above and thenpelletized by a rotary cutter or the like. The method for pelletizationis not limited, but examples thereof include: a method where the resinis withdrawn in a molten state from the final polymerization reactionvessel, cooled/solidified in the form of a strand and then pelletized; amethod where the resin is fed in a molten state from the finalpolymerization reaction vessel to a single- or twin-screw extruder,melt-extruded, cooled/solidified and then pelletized; and a method wherethe resin is withdrawn in a molten state from the final polymerizationreaction vessel, cooled/solidified in the form of a strand and oncepelletized and thereafter, the resin is again fed to a single- ortwin-screw extruder, melt-extruded, cooled/solidified and thenpelletized.

At this time, in the extruder, residual monomers may be devolatilizedunder reduced pressure, and a heat stabilizer, a neutralizing agent, anultraviolet absorber, a release agent, a coloring agent, an antistaticagent, a slip agent, a lubricant, a plasticizer, a compatibilizer, aflame retardant and the like, which are usually known, may be also addedand kneaded.

The melt kneading temperature in the extruder depends on the glasstransition temperature or molecular weight of the polycarbonate resinbut is usually preferably from 150 to 300° C., more preferably from 200to 270° C., still more preferably from 230 to 260° C. By setting themelt kneading temperature to 150° C. or more, the melt viscosity of thepolycarbonate resin is kept low, as a result, the load on the extruderis reduced and the productivity is enhanced. By setting the meltkneading temperature to 300° C. or less, the polycarbonate resin can beprevented from thermal deterioration, making it possible to suppressmechanical strength reduction or coloring due to decrease of themolecular weight, or gas evolution.

At the production of the polycarbonate resin of the present invention, afilter is preferably installed so as to prevent inclusion of anextraneous matter. The filter installation position is preferably on thedownstream side of the extruder, and the rejection size (opening size)of the filter for an extraneous matter is preferably 100 μm or less interms of filtration accuracy for 99% removal. Particularly, in the caseof avoiding inclusion of a fine extraneous matter in the filmapplication or the like, the filtration accuracy is preferably 40 μm orless, more preferably 10 μm or less.

In order to prevent inclusion of an extraneous matter after extrusion,the extrusion of the polycarbonate resin of the present invention ispreferably performed in a clean room having a cleanliness defined in JISB 9920 (2002) of preferably higher than class 7, more preferably higherthan class 6.

Also, at the time of cooling and chip-forming the extruded polycarbonateresin, a cooling method such as air cooling and water cooling ispreferably used. As for the air used in air cooling, an air in which anairborne extraneous matter is previously removed through a hepafilter orthe like is preferably used so as to prevent reattachment of an airborneextraneous matter. In the case of employing water cooling, water inwhich a metallic matter is removed by using an ion-exchange resin or thelike and an extraneous matter in water is removed through a filter, ispreferably used. The opening size of the filter used is preferably from10 to 0.45 μm in terms of filtration accuracy for 99% removal.

<Physical Properties of Polycarbonate Resin>

The molecular weight of the polycarbonate resin of the present inventioncan be expressed by a reduced viscosity, and the reduced viscosity ofthe polycarbonate resin of the present invention is usually preferably0.30 dL/g or more, more preferably 0.35 dL/g or more, and usuallypreferably 1.20 dL/g or less, more preferably 1.00 dL/g or less, stillmore preferably 0.80 dL/g or less.

If the reduced viscosity of the polycarbonate resin is too low, themechanical strength of the molded article tends to be low, whereas ifthe reduced viscosity is too high, there is a tendency that flowabilityat the time of molding the polycarbonate resin composition of thepresent invention is reduced and the productivity and moldability areimpaired.

Incidentally, the reduced viscosity of the polycarbonate resin isdetermined by preparing a solution having a polycarbonate concentrationprecisely adjusted to 0.6 g/dL with use of methylene chloride as asolvent and measuring the viscosity by means of an Ubbelohde viscositytube at a temperature of 20.0° C.±0.1° C.

Furthermore, the lower limit of the concentration of the terminal grouprepresented by the following formula (6) in the polycarbonate resin ofthe present invention is usually preferably 20 μeq/g, more preferably 40μeq/g, still more preferably 50 μeq/g, and the upper limit is usuallypreferably 160 μeq/g, more preferably 140 μeq/g, still more preferably100 μeq/g.

If the concentration of the terminal group represented by formula (6) inthe polycarbonate resin is too high, even when the color hue immediatelyafter polymerization or during molding is good, worsening of the colorhue may be caused after exposure to an ultraviolet ray, whereas if theconcentration is too low, thermal stability may be reduced.

The method for controlling the concentration of the terminal grouprepresented by formula (6) includes, for example, a method ofcontrolling the mol ratio between raw materials, that is, a dihydroxycompound containing the dihydroxy compound (1) and a carbonic aciddiester represented by formula (5), and a method of controlling the kindor amount of a catalyst, the polymerization pressure, or thepolymerization temperature, at the transesterification reaction.

Also, assuming that the molar number of hydrogen bonded to the aromaticring in the polycarbonate resin of the present invention is “X” and themolar number of H bonded to a site other than the aromatic ring is “Y”,the ratio of the molar number of hydrogen bonded to the aromatic ring tothe molar number of all hydrogens is expressed by X/(X+Y), and since thearomatic ring having an ultraviolet absorbing ability may affect thelight resistance as described above, the ratio X/(X+Y) of thepolycarbonate resin of the present invention is preferably 0.1 or less,more preferably 0.05 or less, still more preferably 0.02 or less, yetstill more preferably 0.01 or less. The X/(X+Y) can be quantitativelydetermined by ¹H-NMR.

The glass transition temperature of the polycarbonate resin of thepresent invention is preferably from 75° C. to less than 145° C., morepreferably from 80 to 140° C., still more preferably from 85 to 135° C.By using a polycarbonate resin where the glass transition temperature isin the range above, a molded article having excellent heat resistancecan be provided.

[Elastomer]

The polycarbonate resin composition of the present invention comprisesthe above-described polycarbonate resin of the present invention and anelastomer composed of a core●shell structure, wherein the core layer ofthe elastomer is composed of a butadiene-styrene copolymer. In thedescription of the present invention, the “elastomer composed of acore●shell structure” indicates a core●shell-type graft copolymerconsisting of an innermost layer (core layer) and one or more layers(shell layer) covering the core layer, in which a monomer componentcopolymerizable with the core layer is graft copolymerized as a shelllayer.

The elastomer composed of a core●shell structure for use in the presentinvention is preferably a core●shell-type graft copolymer where,usually, a polymer component called a rubber component is used as thecore layer and a monomer component copolymerizable therewith is graftcopolymerized as the shell layer.

The production process for the core●shell-type graft copolymer may beany of production processes such as bulk polymerization, solutionpolymerization, suspension polymerization and emulsion polymerization,and the mode of copolymerization may be either single-stage graftcopolymerization or multi-stage graft copolymerization. However, in thepresent invention, usually, a commercially available core●shell-typeelastomer can be used as it is. Examples of the commercially availablecore●shell-type elastomer are recited later.

Specific examples of the monomer component constituting a shell layerand being graft-copolymerizable with the polymer component of the corelayer include an epoxy group-containing (meth)acrylic acid estercompound such as aromatic vinyl compound, vinyl cyanide compound,(meth)acrylic acid ester compound, (meth)acrylic acid compound andglycidyl (meth)acrylate; a maleimide compound such as maleimide,N-methylmaleimide and N-phenylmaleimide; and an α,β-unsaturatedcarboxylic acid compound such as maleic acid, phthalic acid and itaconicacid, or an anhydride thereof (for example, maleic anhydride).

One of these monomer components may be used alone, or two or morethereof may be used in combination. Among these, in view of mechanicalcharacteristics or surface appearance, an aromatic vinyl compound, avinyl cyanide compound, a (meth)acrylic acid ester compound and a(meth)acrylic acid compound are preferred, and a (meth)acrylic acidester compound is more preferred.

Specific examples of the (meth)acrylic acid ester compound include analkyl (meth)acrylate such as methyl (meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, andoctyl (meth)acrylate. Among these, methyl (meth)acrylate and ethyl(meth)acrylate, which are relatively easily available, are preferred,and methyl (meth)acrylate is more preferred. Here, the “(meth)acryl” isa term collectively including “acryl” and “methacryl”.

The core●shell-type graft copolymer preferably contains thebutadiene-styrene copolymer component in an amount of 40 wt % or more,more preferably 60 wt % or more. Also, the (meth)acrylic acid estercomponent is preferably contained in an amount of 10 wt % or more.

Specific preferred examples of the core●shell-type graft copolymerinclude a butadiene-styrene-alkyl (meth)acrylate copolymer and abutadiene-styrene-acrylic acid copolymer. In the core●shell-type graftcopolymers exemplified above, the “butadiene-styrene” moiety correspondsto the core layer, and the copolymer is preferably a core●shell-typegraft copolymer where the shell layer is an alkyl (meth)acrylate havingan alkyl group with a carbon number of 1 to 10, such asbutadiene-styrene-methyl (meth)acrylate copolymer,butadiene-styrene-ethyl (meth)acrylate copolymer,butadiene-styrene-methyl (meth)acrylate-ethyl (meth)acrylate copolymer,butadiene-styrene-butyl (meth)acrylate copolymer andbutadiene-styrene-hexyl (meth)acrylate copolymer, a core●shell-typegraft copolymer where the shell layer is a (meth)acrylic acid, such asbutadiene-styrene-acrylic acid copolymer, or a core●shell-type graftcopolymer where both an alkyl (meth)acrylate having an alkyl group witha carbon number of 1 to 10 and a (meth)acrylic acid are used for theshell layer.

Such a core●shell-type graft copolymer includes, for example, “Metablen(registered trademark) C-223A” produced by Mitsubishi Rayon Co., Ltd.

One of these elastomers composed of a core●shell structure, such ascore●shell-type graft copolymer, may be used alone, or two or morethereof may be used in combination.

The polycarbonate resin composition of the present invention preferablycontains the elastomer composed of a core●shell structure in an amountof 0.05 to 50 parts by weight per 100 parts by weight of thepolycarbonate resin of the present invention, and the content is morepreferably 0.1 parts by weight or more, still more preferably 0.5 partsby weight or more, and is preferably 40 parts by weight or less, morepreferably 30 parts by weight or less, still more preferably 25 parts byweight or less. Above all, when the content of the elastomer composed ofa core●shell structure is 3.5 parts by weight or more, a particularlyexcellent effect of improving the impact resistance is obtained.

When the blending amount of the elastomer composed of a core●shellstructure is not more than the upper limit above, this is preferred inview of outer appearance or heat resistance of the molded article, andwhen the blending amount is not less than the lower limit above, it isadvantageously easy to enhance the effect of improving the surfaceimpact resistance or the impact resistance.

[Antioxidant]

The polycarbonate resin composition of the present invention preferablyfurther contains an antioxidant. In the case of using an antioxidant,the content thereof is usually preferably from 0.0001 to 1 wt % based onthe entire polycarbonate resin composition, and the content is morepreferably 0.001 wt % or more, still more preferably 0.01 wt % or more,and is usually preferably 1 wt % or less, more preferably 0.5 wt % orless, still more preferably 0.3 wt % or less.

When the content of the antioxidant is not less than the lower limitabove based on the entire polycarbonate resin composition, the effect ofpreventing coloring during molding tends to be improved. Also, when thecontent of the antioxidant is not more than the upper limit above basedon the entire polycarbonate resin composition, deposits on a metal moldat the injection molding can be prevented from increasing and at thesame time, deposits on a roll when forming a film by extrusion moldingcan be prevented from increasing, making it possible to preventimpairment of the surface appearance of the product.

The antioxidant is preferably at least one member selected from thegroup consisting of a phenol-based antioxidant, a phosphite-basedantioxidant and a sulfur-based antioxidant, more preferably aphenol-based antioxidant and/or a phosphite-based antioxidant.

Examples of the phenol-based antioxidant include pentaerythritoltetrakis(3-mercaptopropionate), pentaerythritoltetrakis(3-laurylthiopropionate), glycerol-3-stearylthiopropionate,triethyleneglycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate],1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,N,N-hexamethylene-bis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide),3,5-di-tert-butyl-4-hydroxy-benzyl phosphonate-diethyl ester,tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene diphosphinate, and3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane.

Among these compounds, an aromatic monohydroxy compound substituted oneor more alkyl group having a carbon number of 5 or more is preferred.Specifically, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,pentaerythritol-tetrakis{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate},1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene andthe like are preferred, andpentaerythritol-tetrakis{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionateis more preferred.

Examples of the phosphite-based antioxidant include triphenyl phosphite,tris(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite,tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite,didecylmonophenyl phosphite, dioctylmonophenyl phosphite,diisopropylmonophenyl phosphite, monobutyldiphenyl phosphite,monodecyldiphenyl phosphite, monooctyldiphenyl phosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite,bis(nonylphenyl)pentaerythritol diphosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and distearylpentaerythritol diphosphite.

Among these, trisnonylphenyl phosphite, trimethyl phosphate,tris(2,4-di-tert-butylphenyl)phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite andbis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite arepreferred, and tris(2,4-di-tert-butylphenyl)phosphite is more preferred.

Examples of the sulfur-based antioxidant includedilauryl-3,3′-thiodipropionic acid ester,ditridecyl-3,3′-thiodipropionic acid ester,dimyristyl-3,3′-thiodipropionic acid ester,distearyl-3,3′-thiodipropionic acid ester, laurylstearyl-3,3′-thiodipropionic acid ester, pentaerythritoltetrakis(3-laurylthiopropionate),bis[2-methyl-4-(3-laurylthiopropionyloxy)-5-tert-butylphenyl]sulfide,octadecyl disulfide, mercaptobenzimidazole,2-mercapto-6-methylbenzimidazole, and 1,1′-thiobis(2-naphthol). Amongthese, pentaerythritol tetrakis(3-laurylthiopropionate) is preferred.

[Releasing Agent]

The polycarbonate resin composition of the present invention preferablycontains a releasing agent. The releasing agent is not particularlylimited but includes, for example a higher fatty acid and a stearic acidester. In view of releasability and transparency, the releasing agent ispreferably a stearic acid ester.

The stearic acid ester is preferably a partial or complete ester of asubstituted or unsubstituted monohydric or polyhydric alcohol having acarbon number of 1 to 20 and a stearic acid. The partial or completeester of a monohydric or polyhydric alcohol and a stearic acid ispreferably, for example, ethylene glycol distearate, monoglyceridestearate, diglyceride stearate, triglyceride stearate, monosorbitatestearate, stearyl stearate, pentaerythritol monostearate,pentaerythritol tetrastearate, propylene glycol monostearate, stearylstearate, butyl stearate, sorbitan monostearate or 2-ethylhexylstearate, more preferably monoglyceride stearate, triglyceride stearate,pentaerythritol tetrastearate or stearyl stearate, still more preferablyethylene glycol distearate or monoglyceride stearate.

The higher fatty acid is preferably a substituted or unsubstitutedsaturated fatty acid having a carbon number of 10 to 30, more preferablya saturated fatty acid having a carbon number of 10 to 30, and examplesof such a higher fatty acid include myristic acid, lauric acid, palmiticacid, stearic acid, and behenic acid. A saturated fatty acid having acarbon number of 16 to 18 is still more preferred, and examples of sucha saturated fatty acid include palmitic acid and stearic acid, withstearic acid being preferred.

One of these releasing agents may be used alone, or two or more thereofmay be mixed and used.

In the case of using a releasing agent, the blending amount thereof isusually preferably 0.001 parts by weight or more, more preferably 0.01parts by weight or more, still more preferably 0.1 parts by weight ormore, and is usually preferably 2 parts by weight or less, morepreferably 1 part by weight or less, still more preferably 0.5 parts byweight or less, per 100 parts by weight of the polycarbonate resin.

If the content of the releasing agent is excessively large, deposits onthe mold during molding may be increased and when molding is performedin a massive scale, a lot of work may be required for maintenance of themold or an appearance failure may be caused in the molded articleobtained. When the content of the releasing agent in the polycarbonateresin composition is not less than the lower limit above, this isadvantageous in that release of the molded article from the mold isfacilitated at the molding and a molded article is easily obtained.

[Other Resins]

In the polycarbonate resin composition of the present invention, a resinother than the polycarbonate resin (hereinafter, sometimes simplyreferred to “other resins”) may be used for the purpose of moreenhancing●adjusting the molding processability or various physicalproperties. Specific examples of other resins include a polyester-basedresin, a polyether, a polyamide, a polyolefin, and a rubbery modifiersuch as linear random or block copolymer. Incidentally, the “rubberymodifier” as used herein does not encompass the “elastomer” named in thedescription of the present invention.

In the case of blending other resins, the blending amount thereof ispreferably from 1 to 30 wt %, more preferably from 3 to 20 wt %, stillmore preferably from 5 to 10 wt %, based on the entire polycarbonateresin composition of the present invention.

[Filler]

In the polycarbonate resin composition of the present invention, afiller, an acidic compound, an ultraviolet absorption aid, a bluingagent, a heat stabilizer, a light stabilizer, an antistatic agent andthe like may be appropriately blended as long as the object of thepresent invention is not impaired. However, the below-describedcomponents are representative examples which can be used, and thepolycarbonate resin composition of the present invention is notprecluded from blending of a component other than those described below.

In the polycarbonate resin composition of the present invention, afiller may be blended as long as the object of the present invention isnot impaired. The filler which can be blended in the polycarbonate resincomposition of the present invention includes, for example, an inorganicfiller and an organic filler.

The blending amount of the filler is preferably from 0 to 100 wt % basedon the entire polycarbonate resin composition. The blending amount ofthe filler is more preferably 50 wt % or less, still more preferably 40wt % or less, yet still more preferably 35 wt % or less. By blending afiller, an effect of stiffening the polycarbonate resin composition isobtained, but if the blending amount is excessively large, the moldedarticle obtained tends to be worsened in the outer appearance.

Examples of the inorganic filler include glass fiber, milled glassfiber, glass flake, glass bead, silica, alumina, titanium oxide, calciumsulfate powder, gypsum, gypsum whisker, barium sulfate, talc, mica andcalcium silicate such as wollastonite; and carbon black, graphite, ironpowder, copper powder, molybdenum disulfide, silicon carbide, siliconcarbide fiber, silicon nitride, silicon nitride fiber, brass fiber,stainless steel fiber, potassium titanate fiber, and a whisker thereof.

Among these, a glass fiber filler, a glass powder filler, a glass flakefiller, various whiskers, mica and talc are preferred; glass fiber,glass flake, milled glass fiber, wollastonite, mica and talc are morepreferred; and glass fiber and/or talc are still more preferred. Onlyone of these inorganic fillers may be used, or two or more thereof maybe used in combination.

As the glass fiber or milled glass fiber, any glass or milled glassfiber used for thermoplastic resins may be used, but among others, afiber composed of alkali-free glass (E glass) is preferred. The diameterof the glass fiber is preferably from 6 to 20 μm, more preferably from 9to 14 μm. If the diameter of the glass fiber is excessively small, thestiffening effect tends to be insufficient, whereas if the diameter isexcessively large, this may adversely affect the outer appearance of themolded article obtained.

Preferred glass fibers include a chopped strand obtained by cutting to alength of 1 to 6 mm, and a milled glass fiber obtained by milling for alength of 0.01 to 0.5 mm, which is commercially available. One of thesemay be used alone, or both may be mixed and used.

In order to enhance the adherence to the polycarbonate resin, the glassfiber may be used after applying a surface treatment, for example, witha silane coupling agent such as aminosilane and epoxysilane, or aconvergence treatment with an acrylic resin, a urethane-based resin orthe like.

As the glass bead, any glass bead used for thermoplastic resin may beused. Among others, a glass bead composed of an alkali-free glass (Eglass) is preferred. The glass bead is preferably a spherical glass beadhaving a particle diameter of 10 to 50 μm.

The glass flake includes a scaly glass flake. The maximum diameter ofthe glass flake blended in the polycarbonate resin composition isgenerally preferably 1,000 μm or less, more preferably from 1 to 500 μm,and the aspect ratio (ratio between maximum diameter and thickness) isusually preferably 5 or more, more preferably 10 or more, still morepreferably 30 or more.

The organic filler includes a powder organic filler such as wood powder,bamboo powder, coconut shell flour, cork flour and pulp powder; aballoon-like or spherical organic filler such as crosslinked polyester,polystyrene, styrene●acrylic copolymer and urea resin; and a fibrousorganic filler such as carbon fiber, synthetic fiber and natural fiber.

The carbon fiber is not particularly limited and includes, for example,various flame-retardant, carbonaceous or graphitic carbon fibers whichare produced through firing by using, as a raw material, an acrylicfiber, a petroleum or carbon-based special pitch, a cellulose fiber, alignin or the like.

The average aspect ratio (fiber length/fiber diameter) of the carbonfiber is preferably 10 or more, more preferably 50 or more. If theaverage aspect ratio is excessively small, the electroconductivity,strength or rigidity of the polycarbonate resin composition tend todecrease. The diameter of the carbon fiber is preferably from 3 to 15μm, and for adjusting the aspect ratio to that described above, any formof chopped strand, roving strand, milled fiber and the like may be used.One carbon fiber may be used, or two or more kinds of carbon fibers maybe mixed and used.

In order to increase the affinity for the polycarbonate resin, thecarbon fiber may be subjected, for example, to a surface treatment suchas epoxy treatment, urethane treatment and oxidation treatment, as longas characteristics of the polycarbonate resin composition of the presentinvention are not impaired.

[Acidic Compound or Derivative Thereof]

The polycarbonate resin composition of the present invention may furthercontain an acidic compound or a derivative thereof.

In the case of using an acidic compound or a derivative thereof, theblending amount of the acidic compound or a derivative thereof ispreferably from 0.00001 to 0.1 wt %, more preferably from 0.0001 to 0.01wt %, still more preferably from 0.0002 to 0.001 wt %, based on theentire polycarbonate resin composition.

When the blending amount of the acidic compound or a derivative thereofis not less than the lower limit above, this is advantageous from thestandpoint of preventing coloring which may occur at the injectionmolding due to a prolonged residence time of the polycarbonate resincomposition in the injection molding machine, but if the blending amountof the acidic compound or a derivative thereof is too large, hydrolysisresistance of the polycarbonate resin composition may be reduced.

Examples of the acidic compound or a derivative thereof include aBroensted acid such as hydrochloric acid, nitric acid, boric acid,sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid,hypophosphorous acid, polyphosphoric acid, adipic acid, ascorbic acid,aspartic acid, azelaic acid, adenosine phosphate, benzoic acid, formicacid, valeric acid, citric acid, glycolic acid, glutamic acid, glutaricacid, cinnamic acid, succinic acid, acetic acid, tartaric acid, oxalicacid, p-toluenesulfinic acid, p-toluenesulfonic acid,naphthalenesulfonic acid, nicotinic acid, picric acid, picolinic acid,phthalic acid, terephthalic acid, propionic acid, benzenesulfinic acid,benzenesulfonic acid, malonic acid and maleic acid, and esters thereof.Among these acidic compounds or derivatives thereof, sulfonic acids oresters thereof are preferred, and p-toluenesulfonic acid, methylp-toluenesulfonate, and butyl p-toluenesulfonate are more preferred.

Such an acidic compound or a derivative thereof may be added in theproduction step of the polycarbonate resin composition as a compound forneutralizing the basic transesterification catalyst used in theabove-described polycondensation reaction of the polycarbonate resin.

[Ultraviolet Absorber]

In the polycarbonate resin composition of the present invention, anultraviolet absorber can be blended as long as the object of the presentinvention is not impaired. The blending amount of the ultravioletabsorber may be appropriately selected according to the kind of theultraviolet absorber, but the ultraviolet absorber is preferably blendedin an amount of 0 to 5 wt % based on the entire polycarbonate resincomposition.

Here, the ultraviolet absorber is not particularly limited as long as itis a compound having an ultraviolet absorbing ability. The compoundhaving an ultraviolet absorbing ability includes, for example, anorganic compound and an inorganic compound. Of these, an organiccompound is preferred, because its affinity for the polycarbonate resinis easily secured to facilitate uniform dispersion.

The molecular weight of the organic compound having an ultravioletabsorbing ability is not particularly limited but is usually preferably200 or more, more preferably 250 or more, and is usually preferably 600or less, more preferably 450 or less, still more preferably 400 or less.If the molecular weight is excessively small, reduction in theultraviolet-resistance performance may be caused in long-term use,whereas if the molecular weight is excessively large, reduction in thetransparency of the resin composition may be caused in long-term use.

Preferred examples of the ultraviolet absorber include abenzotriazole-based compound, a benzophenone-based compound, atriazine-based compound, a benzoate-based compound, a phenyl salicylateester-based compound, a cyanoacrylate-based compound, a malonic acidester-based compound, and an oxalic anilide compound. Among these, abenzotriazole-based compound, a hydroxybenzophenone-based compound and amalonic acid ester-based compound are more preferred. One of thesecompounds may be used alone, or two or more thereof may be used incombination.

More specifically, examples of the benzotriazole-based compound include2-(2′-hydroxy-3′-methyl-5′-hexylphenyl)benzotriazole,2-(2′-hydroxy-3′-tert-butyl-5′-hexylphenyl)benzotriazole,2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole,2-(2′-hydroxy-3′-methyl-5′-tert-octylphenyl)benzotriazole,2-(2′-hydroxy-5′-tert-dodecylphenyl)benzotriazole,2-(2′-hydroxy-3′-methyl-5′-tert-dodecylphenyl)benzotriazole,2-(2′-hydroxy-5′-tert-butylphenyebenzotriazole, andmethyl-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate.

Examples of the benzophenone-based compound include ahydroxybenzophenone-based compound such as 2,2′-dihydroxybenzophenone,2,2′,4,4′-tetrahydroxybenzophenone and 2-hydroxy-4-octoxybenzophenone.

Examples of the malonic acid ester-based compound include2-(1-arylalkylidene)malonic acid esters andtetraethyl-2,2′-(1,4-phenylene-dimethylidene)-bismalonate.

Examples of the triazine-based compound include2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-s-triazine,and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (Tinuvin1577FF, produced by Ciba-Geigy). Incidentally, brominated triazinerecited above as the flame retardant is a triazine-based compound but,in the description of the present invention, this compound is notregarded as an ultraviolet absorber and is classified into the flameretardant.

Examples of the cyanoacrylate-based compound includeethyl-2-cyano-3,3-diphenyl acrylate and2′-ethylhexyl-2-cyano-3,3-diphenyl acrylate.

Examples of the oxalic anilide-based compound include2-ethyl-2′-ethoxy-oxalanilide (Sanduvor VSU, produced by Clariant).

[Bluing Agent]

In the polycarbonate resin composition of the present invention, abluing agent may be blended so as to cancel the yellow tint attributableto the polycarbonate resin or ultraviolet absorber. As for the bluingagent, a bluing agent conventionally employed for polycarbonate resinsmay be used without any problem. In general, an anthraquinone-based dyeis easily available and preferred.

Specific representative examples of the bluing agent include SolventViolet 13, popular name [CA. No. (Color index No.) 60725], SolventViolet 31, popular name [CA. No. 68210], Solvent Violet 33, popular name[CA. No. 60725], Solvent Blue 94, popular name [CA. No. 61500], SolventViolet 36, popular name [CA. No. 68210], Solvent Blue 97, popular name[MACROLEX VIOLET RR, produced by Bayer AG], and Solvent Blue 45, popularname [CA. No. 61110]. One of these bluing agents may be used alone, ortwo or more thereof may be used in combination.

The bluing agent is usually blended in a ratio of preferably from0.1×10⁻⁵ to 2×10⁻⁴ wt % based on the entire polycarbonate resincomposition.

[Light Stabilizer]

For the purpose of more improving the light resistance of thepolycarbonate resin composition and polycarbonate resin molded articleof the present invention, a light stabilizer can be blended in thepolycarbonate resin composition of the present invention.

Examples of the light stabilizer includebis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis-(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}],anN,N′-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidylamino)-6-chloro-1,3,5-triazinecondensate, and a polycondensate ofdibutylamine●1,3,5-triazine●N,N-bis(2,2,6,6)-tetramethyl-4-piperidyl-1,6-hexamethylenediamineand N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine. Among these,bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate andbis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate are preferred.

In the case of using the light stabilizer, the light stabilizer ispreferably blended in a ratio of 0 to 2 wt %, more preferably from 0.005to 0.5 wt %, still more preferably from 0.01 to 0.2 wt %, based on theentire polycarbonate resin composition of the present invention.

By blending such a light stabilizer, the light resistance of the moldedarticle obtained by molding the polycarbonate resin composition of thepresent invention can be enhanced without causing bleed out to thesurface of the polycarbonate resin composition and reduction in themechanical characteristics of the molded article obtained.

[Other Additives]

In the polycarbonate resin composition of the present invention, anantistatic agent may be further incorporated as long as the object ofthe present invention is not impaired. Furthermore, in the polycarbonateresin composition of the present invention, as long as the object of thepresent invention is not impaired, various additives such as heatstabilizer, neutralizer, coloring agent, slip agent, lubricant,plasticizer, compatibilizer and flame retardant may be blended, otherthan those described above.

[Timing of Adding and Method for Adding Various Additives]

The timing of adding and method for adding the above-described variousadditives blended in the polycarbonate resin composition, such asantioxidant, release agent, filler or acidic compound or its derivative,ultraviolet absorption aid, bluing agent, heat stabilizer, lightstabilizer and antistatic agent, are not particularly limited.

The timing of adding the additives includes: for example, in the case ofproducing the polycarbonate resin by a transesterification method, whenthe polymerization reaction is completed; and irrespective of thepolymerization method, when the polycarbonate resin or polycarbonateresin composition is in a melted state, such as during melt-kneading ofthe polycarbonate resin and other compounding agents, or when thepolycarbonate resin composition that is in a solid state such as pelletand powder is blended●kneaded using an extruder or the like.

The method for adding additives includes, for example, a method ofdirectly mixing or kneading various components with the polycarbonateresin, and a method of adding a high-concentration master batch preparedusing a small amount of the polycarbonate resin composition, otherresins or the like and various components.

[Production Process]

The polycarbonate resin composition of the present invention can beproduced by mixing raw materials, that is, the polycarbonate resin andthe elastomer composed of a core●shell structure of the presentinvention and furthermore, if desired, other resins or variousadditives, simultaneously or in an arbitrary order by means of atumbler, a super-mixer, a floater, a V-blender, a Nauta mixer, a Banburymixer, an extruder or the like.

[Polycarbonate Resin Molded Article]

The polycarbonate resin composition of the present invention is molded,whereby the polycarbonate resin molded article of the present inventionis obtained.

The polycarbonate resin molded article of the present invention can beproduced by directly mixing raw materials such as polycarbonate resin,elastomer and, if desired, other resins or additives, charging themixture into an extruder or an injection molding machine, and moldingit, or by melt-mixing the raw materials above by means of a twin-screwextruder, extruding the molten mixture in strand form to produce apellet, charging the pellet into an extruder or an injection moldingmachine, and molding it.

The molding method is not particularly limited, and a commonly knownmethod such as injection molding method, extrusion molding method andcompression molding method may be employed, but in view of degree offreedom for the molded article shape, an injection molding method ispreferred.

The polycarbonate resin molded article obtained by molding thepolycarbonate resin composition of the present invention is excellentparticularly in the impact resistance and therefore, can be suitablyused for application as a smoke film or the like of, for example, anelectric●electronic component, an automotive component, a sheet, abottle, a container, a building material and a glass window. Amongothers, when the total light transmittance of the polycarbonate resincomposition is less than 60%, the molded article is useful particularlyfor application, for example, as a smoke film on glass window and thelike, as a privacy glass for automobiles and the like, or as aglass-alternative building material such as windowpane.

Incidentally, the “film” generally indicates a thin flat product inwhich the thickness is extremely small as compared with the length andwidth and the maximum thickness is arbitrarily limited, and the “sheet”generally indicates a flat product which is thin by definition of JISand is small in the thickness for its length and width.

However, the border between the “sheet” and the “film” is not definiteand in the present invention, these two terms need not be distinguished.Therefore, in the present invention, even when “film” is referred to,this encompasses “sheet”, and even when “sheet” is referred to, thisencompasses “film”. The same applies to the “smoke film” above.

EXAMPLES

The present invention is described in greater detail below by referringto Examples, but the present invention is not limited to these Examplesas long as its purport is observed. In the following Examples, thevalues of various production conditions or evaluation results have ameaning as a preferred value of the upper or lower limit in theembodiment of the present invention, and the preferred range may be arange defined by a combination of the upper or lower limit valuedescribed above and the value in Example or a combination of values inExamples.

In the following, each raw material or additive used in the productionsof polycarbonate resin and polycarbonate resin compositions is indicatedby the following abbreviation.

<Dihydroxy Compound>

-   ISB: Isosorbide “POLYSORB” produced by Roquette Fr eres-   CHDM: 1,4-Cyclohexanedimethanol produced by Eastman Ltd.    <Carbonic Acid Diester>-   DPC: Diphenyl carbonate (produced by Mitsubishi Chemical Corp.)    <Elastomer>    C-223A:

Core●shell-type elastomer “Metablen (registered trademark) C-223A”produced by Mitsubishi Rayon Co., Ltd. (an elastomer of acore●shell-type graft copolymer where the core layer is abutadiene-styrene copolymer and the shell layer is a methyl methacrylatepolymer) EXL2603:

Core●shell-type elastomer “Paraloid (registered trademark) EXL2603”produced by Rohm and Haas JAPAN K.K. (an elastomer of a core●shell-typegraft copolymer where the core layer is a butadiene polymer and theshell layer is an alkyl acrylate-alkyl methacrylate copolymer)

S-2001:

Core●shell-type elastomer “Metablen (registered trademark) S-2001”produced by Mitsubishi Rayon Co., Ltd. (an elastomer of acore●shell-type graft copolymer where the core layer is asilicon●acrylic composite and the shell layer is a methyl methacrylatepolymer)

W-450A:

Core●shell-type elastomer “Metablen (registered trademark) W-450A”produced by Mitsubishi Rayon Co., Ltd. (an elastomer of acore●shell-type graft copolymer where the core layer is an alkylacrylate polymer and the shell layer is a methyl methacrylate polymer)

<Antioxidant>

Adekastab 2112:

Phosphite-based antioxidant “Adekastab (registered trademark) 2112”produced by ADEKA Corporation

Adekastab AO-60:

Phenol-based antioxidant “Adekastab (registered trademark) AO-60”produced by ADEKA Corporation

<Release Agent>

S-100A:

Stearic monoglyceride produced by Riken Vitamin Co., Ltd.

Also, the reduced viscosity of the polycarbonate resin and the impactresistance of the polycarbonate resin composition were measured andevaluated by the following methods.

[Reduced Viscosity of Polycarbonate Resin]

The polycarbonate resin was dissolved using methylene chloride as asolvent to prepare a polycarbonate resin solution having a concentrationof 0.6 g/dL, and the solution was measured at a temperature of 20.0°C.±0.1° C. by using an Ubbelohde viscosity tube manufactured by MoritomoRika Kogyo. The relative viscosity η_(rel) was obtained from theflow-through time t₀ of the solvent and the flow-through time t of thesolution according to the following formula (i), and the specificviscosity η_(sp) was obtained from the relative viscosity according tothe following formula (ii):η_(rel) =t/t ₀  (i)η_(sp)=(η−η₀)/η₀=η_(rel)−1  (ii)

The reduced viscosity η_(sp)/c was determined by dividing the specificviscosity by the concentration c (g/dL).

A higher value indicates a larger molecular weight.

[Impact Resistance of Polycarbonate Resin Composition]

A pellet of the polycarbonate resin composition was dried at 80° C. for6 hours by using a hot-air drier. The dried polycondensation resincomposition pellet was then fed to an injection molding machine (ModelJ75EII, manufactured by The Japan Steel Works, Ltd.), and an ISO testspecimen for mechanical properties was molded under the conditions of aresin temperature of 240° C., a mold temperature of 60° C. and a moldingcycle of 40 seconds. This ISO test specimen for mechanical propertieswas subjected to a notched Charpy impact test in accordance with ISO 179(2000) and evaluated for the impact resistance.

[Total Light Transmittance of Polycarbonate Resin Composition]

In accordance with JIS K7105 (1981), the total light transmittance inthe thickness direction of the injection molded plate (60 mm (width)×60mm (length)×3 mm (thickness)) obtained above was measured with a D65light source by using a haze meter (NDH2000 manufactured by NipponDenshoku Industries Co., Ltd.).

Production Example 1

Into a polymerization reaction apparatus equipped with a stirring bladeand a reflux condenser controlled to 100° C., ISB, CHDM, DPC adjusted toa chloride ion concentration of 10 ppb or less by distillationpurification, and calcium acetate monohydrate were charged to give amolar ratio of ISB/CHDM/DPC/calcium acetatemonohydrate=0.50/0.50/1.00/1.3×10⁻⁶, and thereafter, the apparatus wasthoroughly purged with nitrogen (oxygen concentration; from 0.0005 to0.001 vol %).

Subsequently, the apparatus was heated with a heat medium, and when theinternal temperature reached 100° C., stirring was started. The contentswere melted while controlling the system to keep the internaltemperature at 100° C. and thereby made uniform. Thereafter, heating wasstarted, and the internal temperature was raised to 210° C. over 40minutes. When the internal temperature reached 210° C., the system wascontrolled to keep this temperature and at the same time, pressurereduction was started. The pressure was reduced to 13.3 kPa (absolutepressure, hereinafter the same) over 90 minutes after reaching 210° C.,and the system was held for further 60 minutes while keeping thispressure.

A phenol vapor generated as a by-product with the progress ofpolymerization reaction was introduced into the reflux condenser using,as a cooling medium, steam that was controlled to 100° C. in terms ofthe temperature at the inlet of the reflux condenser. Monomer componentscontained in a slight amount in the phenol vapor were returned to thepolymerization reaction vessel, and uncondensed phenol vapor wassubsequently introduced into a condenser using, as a cooling medium,warm water at 45° C. and recovered.

After the pressure was once returned to atmospheric pressure, thethus-oligomerized contents were transferred to another polymerizationreaction apparatus equipped with a stirring blade and a reflux condensercontrolled in the same manner as above, and heating and pressurereduction were started so as to raise the internal temperature to 220°C. and reduce the pressure to 200 Pa, over 60 minutes.

Thereafter, the internal temperature and the pressure were adjusted to230° C. and 133 Pa or less, respectively, over 20 minutes, and when apredetermined stirring power was achieved, the pressure was returned toatmospheric pressure. The contents were withdrawn in the form of astrand and then pelletized by a rotary cutter. The reduced viscosity ofthe obtained pellet was measured and found to be 0.60 dL/g.

Production Example 2

A polycarbonate resin pellet was obtained in the same manner as inProduction Example 1 except for changing the mol ratio between ISB andCHDM to ISB/CHDM=0.70/0.30. The reduced viscosity of the obtained pelletwas measured and found to be 0.48 dL/g.

Example 1, Comparative Examples 1 to 4

Using the polycarbonate resin pellet produced in Production Example 1,respective components were blended in accordance with the formulationshown in Table-1. The mixture was extruded at a resin temperature of250° C. by using a twin-screw extruder (TEX30HSS-32) manufactured by TheJapan Steel Works, Ltd., and the extrudate was cooled/solidified withwater and then pelletized by a rotary cutter. The thus-producedpolycarbonate resin composition was measured for the impact resistance.The results obtained are shown in Table-1.

Example 2, Comparative Examples 5 and 6

Using the polycarbonate resin pellet produced in Production Example 2,respective components were blended in accordance with the formulationshown in Table-2. The mixture was extruded at a resin temperature of250° C. by using a twin-screw extruder (TEX30HSS-32) manufactured by TheJapan Steel Works, Ltd., and the extrudate was cooled/solidified withwater and then pelletized by a rotary cutter. The thus-producedpolycarbonate resin composition was measured for the impact resistance.The results obtained are shown in Table-2.

Example 3, Comparative Examples 7 to 9

Using the polycarbonate resin pellet produced in Production Example 1,respective components were blended in accordance with the formulationshown in Table-3. The mixture was extruded at a resin temperature of250° C. by using a twin-screw extruder (TEX30HSS-32) manufactured by TheJapan Steel Works, Ltd., and the extrudate was cooled/solidified withwater and then pelletized by a rotary cutter. The thus-producedpolycarbonate resin composition was measured for the impact resistance.The results obtained are shown in Table-3.

TABLE 1 Comparative Comparative Comparative Comparative Example 1Example 1 Example 2 Example 3 Example 4 Formulation of PolycarbonateProduction Example 1 parts by 100 100 100 100 100 Polycarbonate resin(ISB/CHDM = 50/50) weight Resin Elastomer Metablen C-223A parts by 5.29— — — — Composition weight Paraloid EXL2603 parts by — — 5.29 — — weightMetablen S-2001 parts by — — — 5.29 — weight Metablen W-450A parts by —— — — 5.29 weight Antioxidant Adekastab AS2112 parts by 0.05 0.05 0.050.05 0.05 weight Adekastab AO-60 parts by 0.11 0.10 0.11 0.11 0.11weight Release agent S-100A parts by 0.32 0.30 0.32 0.20 0.32 weightEvaluation Impact resistance Notched Charpy kJ/m² 131 11 29 25 26Results impact strength Light-blocking Total light % 72 90 83 47 53effect transmittance *1: In the Table, “—” indicates that the materialwas not used.

TABLE 2 Comparative Comparative Example 2 Example 5 Example 6Formulation of Polycarbonate resin Production Example 2 parts by weight100 100 100 Polycarbonate Resin (ISB/CHDM = 70/30) Composition ElastomerMetablen C-223A parts by weight 5.29 — — Paraloid EXL2603 parts byweight — — 5.29 Antioxidant Adekastab AS2112 parts by weight 0.05 0.050.05 Adekastab AO-60 parts by weight 0.11 0.10 0.11 Release agent S-100Aparts by weight 0.32 0.30 0.32 Evaluation Results Impact resistanceNotched Charpy impact kJ/m² 17 7 15 strength Light-blocking effect Totallight transmittance % 79 89 85 *1: In the Table, “—” indicates that thematerial was not used.

TABLE 3 Comparative Comparative Comparative Example 3 Example 7 Example8 Example 9 Formulation of Polycarbonate Production Example 1 parts byweight 100 100 100 100 Polycarbonate resin (ISB/CHDM = 50/50) ResinComposition Elastomer Metablen C-223A parts by weight 11.11 — — —Paraloid EXL2603 parts by weight — 11.11 — — Metablen S-2001 parts byweight — — 11.11 — Metablen W-450A parts by weight — — — 11.11Antioxidant Adekastab AS2112 parts by weight 0.05 0.05 0.05 0.05Adekastab AO-60 parts by weight 0.11 0.11 0.11 0.11 Release agent S-100Aparts by weight 0.32 0.32 0.20 0.32 Evaluation Results Impact resistanceNotched Charpy impact kJ/m² 86 83 72 68 strength Light-blocking Totallight transmittance % 57 69 30 37 effect *1: In the Table, “—” indicatesthat the material was not used.

As seen from these results, according to the polycarbonate resincomposition of the present invention, a polycarbonate resin moldedarticle excellent in the impact resistance is obtained. Furthermore, itis understood that as seen in Example 3 of Table-3, a polycarbonateresin composition excellent in the impact resistance and having a totallight transmittance of less than 60% is obtained. Such a polycarbonateresin composition is suitably used in particular for a glass-alternativebuilding material or a smoke film or the like of, for example, glasswindow, in the application requiring a material which must have impactresistance, nevertheless, be low in the total light transmittance, suchas in privacy glass for automobiles and the like or in smoked glass forwindow building materials.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope of the invention. This applicationis based on Japanese Patent Application (Patent Application No.2011-079416) filed on Mar. 31, 2011, the entirety of which isincorporated herein by way of reference.

The invention claimed is:
 1. A polycarbonate resin composition, comprising: a polycarbonate resin having a glass transition temperature of less than 145° C. and containing a structural unit derived from a dihydroxy compound having a moiety represented by the following formula (1); and an elastomer composed of a core●shell structure, wherein a core layer of the elastomer is composed of a butadiene-styrene copolymer:

CH₂—O

  (1) provided that a case where the moiety represented by formula (1) is a moiety constituting —CH₂—O—H is excluded.
 2. The polycarbonate resin composition according to claim 1, wherein when the polycarbonate resin composition is formed into a molded body of 3 mm in thickness, a total light transmittance is less than 60%.
 3. The polycarbonate resin composition according to claim 1, comprising the elastomer in an amount of 0.05 to 50 parts by weight per 100 parts by weight of the polycarbonate resin.
 4. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin contains a structural unit derived from a dihydroxy compound having a cyclic structure.
 5. The polycarbonate resin composition according to claim 4, wherein the polycarbonate resin contains a structural unit derived from a dihydroxy compound represented by the following formula (2):


6. The polycarbonate resin composition according to claim 1, wherein a shell layer of the elastomer is composed of an alkyl (meth)acrylate.
 7. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin contains a structural unit derived from an aliphatic dihydroxy compound.
 8. The polycarbonate resin composition according to claim 7, wherein the polycarbonate resin contains the structural unit derived from an aliphatic dihydroxy compound in an amount of 20 mol% or more based on structural units derived from all dihydroxy compounds.
 9. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin contains a structural unit derived from at least one dihydroxy compound selected from the group consisting of a dihydroxy compound having a 5-membered ring structure and a dihydroxy compound having a 6-membered ring structure.
 10. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin contains a structural unit derived from at least one dihydroxy compound selected from the group consisting of cyclohexanedimethanols and tricyclodecanedimethanols.
 11. A polycarbonate resin molded article, which is obtained by molding the polycarbonate resin composition according to claim
 1. 12. The polycarbonate resin molded article according to claim 11, which is obtained by injection-molding the polycarbonate resin composition.
 13. The polycarbonate resin composition according to claim 1, wherein the glass transition temperature is at least 75° C.
 14. The polycarbonate resin composition according to claim 1, wherein the glass transition temperature is from 80 to 140° C.
 15. The polycarbonate resin composition according to claim 1, wherein the glass transition temperature is from 85 to 135° C. 